Engine starting mechanism



May 1, 1945.

A TTORNEY Patented May 1, 1945 ENGINE STARTING MECHANISM Samuel Gilbert,Verona, N. J., assignor to Bendix Aviation Corporation, South Bend,Ind., a corporation of Delaware Application March 9, 1942, Serial No.433,995

(Cl. 12S-179) 2 Claims.

This invention relates to engine starting mechanism and moreparticularly to a starting mechanism of the inertia type, in which thereis a period of energy storage in an inertia" element (ilywheel, -forexample) prior to any rotation of the member of the engine to whichinitial rotary movement is to be imparted.

Objects of the present invention are to make advantageous use of all theenergy of the ywheel all the Way downto zero flywheel speed; and tominimize the shock of engagement. The latter I propose to bring about byengaging the starter and engine jaws at zero rotary speed, thenaccelerating the flywheel (the jaws remaining engaged but not rotating);and thereafter, beginning the rotation of the starter jaw.

Still another object is to produce a direct cranking action by use ofenergy from a prime mover additional to the flywheel, said prime moverbeing operative, lirst, to accelerate the fly-- wheel, andsubsequently-and Without reversal in its direction of rotation-#beinginstrtunental in helping the flywheel to speed up the engine andcontinue to transfer energy thereto even after the flywheel has come toa complete stop, and so long as is necessary to insure effectivestarting. l

These and other objects ci the invention will 4become apparent frominspection of ythe follown ing specification when read with reference tothe accompanying drawing, wherein is illustrated the preferredembodiment of the invention. lt ls to -be expressly understood, however,that thedrawing is for the purpose of illustration only, and is notdesigned as a definition of the limits of the invention, referencebeinghad tothe appended claims for this purpose.

The invention is illustrated in the accompanying drawing as embodied in-a housing having an outer section 3 and an inner section 4 with asuitable flange '5 to receive bolts-6 for detachably connecting saidsections. Theinner section 4` is provided with a second flange 'I toreceive.bolts--' 9 or-securlng'the starter tothe crankcase o'f an. 5

engine, a4 portion of the latter being indicated at'9.. 1Secured tosection 3 is an electric motor Ill providedwith a casing I l having aflange to regis-4 ter 'with a corresponding flange on'casing section 3',and be supported thereby.

The motor may be of any suitable type embodying an armature shaft i3provided with a projecting, reduced portion` I4 that is rotatablymounted as by means of a suitable bearing l5 in the armature shaft is anannular gear I8 that meshes with planet pinions I1 driving a centralpinion I6. Adjacent the member I8 is a cylindrical boss I9 forming partof a transverse wall secured tohousing section 3. The boss I9 supportstherein a double bearing 20 Within which rotates the hub 2l of theflywheel 22, also the shaft 23 to which said hub 2| is keyed asindicated. At its end the shaft 23 is formed into the pinion I6,constituting the sun, or central element of the planetary system whoseseveral planet pinions, as at I1 and 2l, mesh with the orbital `gear Itheretofore referred to.

A second planetary system includes a planet carrier 38 integral with asun gear 39, and is rotatably mounted as by means of a bearing il on astub shaft 42 that extends outwardly from, and is drivably connected to,a barrel i3 having a closed end M, the stub shaft being integral withsaid closed end in the illustrated embodiment olf the invention. Ballbearings 3l] carried by the inner housing section Il are preferablyemployed for rotatably mounting the barrel it.

Gear i9 meshes with a plurality of planetary gears it that are rotatablymounted on the barrel end all! and mesh with an annulus gear which isixedly mounted within the housing by means of studs it. Preferably threeplanetary gears tt are employed, and, one of these is shown in sectionin Fig. l. These gears EI are preferably spaced 120 apart, so that asthe View, is taken in Fig. l, one of the gears appears in elevation lustbelow the stub'shaft t2. Each of the planetary gears it (and the sameis' true of planets I'I, 21) is rotatably'mounted by means of a ballbearing, as at 5I, carried by a sleeve which is countersunl; at itsinner Vencl in barrel end dfi. Ascrew 52 supports each sleeve, bearingand ,l tegralpart of the screw receiving sleeves.

a transversely extending-wallof housing section 3. Drivably connected tothe reduced portion of As shown,-`annulus 41- has two orbital tracks,

the second being engaged by planet pinions'li rotatably mounted (bypartssimilar Vto those supporting pinions' 5I) to turn with carrier `3B abovedescribed, and each meshngwith a sun gear 51 formed onone end ofan'annular gear with gear' ina manner to be described.

The electric motor I is adapted to drive an engine engaging member B4through the train of reduction gearing described above. The member 6 4constitutes one element of a jaw clutch, the

.other elementbeng Aformed by a meinber- S6, 55

carried by a rotating part of the engine to be Central pinion 6I andplanets 59, Ell coactV v cranked, such as the engine crankshaft or an,

extension thereof. There is also preferably employed the usual multipledisk clutch embodying a plurality of friction disks 69, a number of saiddisks being splined to the inner surface of barrel 43, and the remainderbeing splined to the outer surface of an interiorly threaded nut 1|.Resilient means such as a plurality of coil springs 12 and an adjustingnut 13, whichis threaded into the inner end of barrel 43, are providedfor varying the pressure with which disks 69 are maintained inengagement.

Mounted for rotary and longitudinal movement within nut 1| is the usualthreaded shaft 14 which is longitudinally splined at its inner end todrivably engagea correspondingly splined, tubular and outwardlyextending portion 64a of the jaw clutch member 64. Movement of threadedshaft 'it to the left, as viewed in Fig. 1, relative to nut 1| ispositively limited by means of a member 16 threaded on the outer end ofshaft 14 and constituting a stop for engagement with a shoulder formedinteriorly of nut 1| Preferably a coil spring 78 is interposed betweenjaw clutch member 64 and shaft 14, a portion of said spring extendinginto a recess formed in the inner end of the shaft, to yieldingly resistrelative movement of the parts.

The starter is preferably provided with the usual oil sealing means forpreventing oil in the engine crankcase 9 from seeping into the starterhousing. This includes a cup-shaped member 8| that is preferably formedof metal and is provided with a flange 82 on the outer end thereof, saidflange being adapted to be clamped between flange 1 of the starterhousing and the engine crankcase. 'Ihe inner portion of member 8| isbent inwardly toward jaw member 64, and is provided with a centralopening which is slightly larger in diameter than the outer diameter ofthe head of jaw member 64.

In order to prevent seepage of oil through the central opening in member8|, the latter preferably carries the usual washer of leather or thelike, secured in any suitable manner to the shoulder provided adjacentthe bend of member 8|. Normally the inner portion of the washer is heldinengagement with the adjacent surface of the head of jaw member 64 bymeans of a sleeve which slidably surrounds the cylindrical portion 64aof the jaw clutch member and abuts at its outer end against a flangeprovided on nut 1|. The outer periphery of the head of member 8| isprovided with longitudinally disposed slots adapted to receive radiallugs which project inwardly from the inner surface of a split-ring 9|that is supported on the curved lip of the oil seal member 8|. Theseveral portions of the split-ring 9 I are preferably retained inposition on member 8| by means of a surrounding resilient member, suchas a coil spring 92, which rests in a circular groove formed in theouter periphery of said ring 9|. The latter is adapted to rotate on thecurved lip surrounding the central opening in member 8|; thisconstruction being more fully illustrated in Patent No. 1,962,397,granted to Raymond P. Lansing on June 12, 1934.

There is also preferably provided the usual rod 96 which slidablyextends through stub shaft 42, barrel end 44, threaded shaft 14 and acentral opening in the hub of member 8|. The inner portion of rod 96 isof reduced diameter to provide a shoulder 98 which normally abutsagainst the outer end of shaft 14. The inner end of rod 96 is threadedto receive a nut which abuts the hub of jaw member 64 and coacts withshoulder to retain said member and shaft in operative relationship.

A brake shoe" or friction ring |0| is suitably secured to an obliquesurface of orbital track 41, and is engageable by a correspondinglyshaped surface on a brake element |02 when the latter is shifted alongthe splines |03 on the periphery of planet carrier |04. A spring |06 hasone end abutting the flange of track 41, and its central portion windsaround a pin |01; the opposite end of the spring being so formed as tooperatively engage the shifter arm |08. Brake |02 has a peripheralgroove |09 to receive the yoke portion ||8 of the shifter arm |08, and alink pivotally receives the outer end of arm |08. Link may be actuatedby a solenoid, or manually, or by any other suitable means. Pins ||2support the planets 59, 60 for unitary rotation with their carrier |04,and the latter is rotatively supported on the outer race of bearing ||3.Bearing ||3 surrounds the reduced end IIG of shaft |3|4, and a sleeve(on which central pinion 6| is formed) is keyed to said reduced end ||6.

In operation, motor |0 is energized, whereupon shaft |4 causes gears |8,I1, 21, |6 and 6| to rotate. Rotation of gear |6 produces correspondingrotation of flywheel 22. Rotation of the sun gear causes rotation of theplanet gears 59 and 60 about their axes with the result that the orbitalgear 58 is rotated. The rotation of the orbital gear being occasioned bythe coaction between the inertia of the pinions 59 and 60, brakeelement; |02 and the sudden rotation and high rate of acceleration ofthe armature shaft I3 in response `to motor energization. When theorbital gear is thus rotated, the friction and inertia of the secondgear train, the clutch mechanism and the screw shaft 14 are overcomewith the result that the shaft 14 is axially shifted thereby causing thejaw 64 to engage the engine jaw 66. Immediately upon such engagement,the entire gear train-that is, from gear 58 to the screw shaft 14-comesto a standstill, for the turning effort is, as yet, insulflcient toovercome the static inertia of the engine to which the jaw is attached.This stoppage of gear 58, however, does not interfere with continuedrotation of shaft I4, due to the planetary nature of the connection fromsun gear 6| to orbital gear 58. Hence shaft 4 continues to operate toaccelerate the ywheel 22, by way of gears I8, |1, 21 and I6, and inresponse to the continuing flow of current to motor I0.

When the operator is satisfied that flywheel 22 has been brought to fullacceleration, so that the storage of energy is sufficient to assureinitial rotation of engine member 66, he actuates link to throw brakeelementI |02 into engagement with the stationary friction band |0|,whereupon planet carrier |04 is brought to rest, and a reaction isproduced upon orbital gear 58 to rotate said orbital gear-the sun gear6| being now in rotation at high speed-and thus is set in motion theentire gear train extending from orbital gear 58 to the engaged jaws 64and 66. In this manner the engine is turned over, and the energypreviously stored in flywheel is thus transferred to the engine.

During this energy transfer the motor |0 may continue to receive current(from any4 suitable practice) and such conof the motor providesadditional cranking energy, which additional cranking energy maycontinue to be supplied for as long a period as is desirable to assureagainst any loss of cranking momentum. 0f course, as soon as the enginefuel combustion becomes regular, the jaw 6B will accelerate beyond thecranking speed of jaw 64, whereupon the shaft 14 will bereverse-threaded back to the jaw-retracting position, as in allscrew-engaged starter drives. Upon this occurrence there is. of course,no need for further energization of motor I0, and therefore the operatorwill open the circuit thereto. At the same time the operator willrelease the link III, allowing spring |06 to return brake element |02 tothe non-braking position illustrated.

What is claimed is:

l. In an engine starter, a motor, a flywheel, an engine-engaging member,means responsive to rotation of the motor to move said engine-engagingmember to engine-engaging position, said means including a planetarygear train having an orbital element which is brought to a stop by saidengine-engaging member when said engine-engaging member reachesengine-engaging position, and also including a planet carrier whichcontinues to rotate with said motor, means for drivably connecting saidmotor and flywheel, and means for stopping the rotation of said planetcarrier and thereby causing the rotation of said motor and. flywheel tobe communicated to said engine-engaging member, by way of said orbitalelement.

2. In an engine starter, a motor, an engineengaging member, meansresponsive to rotation of the motor to move said engine-engaging memberto engine-engaging position, said means including, a planetary geartrain having an orbital element which is brought to a stop by saidengineengaging member, when said engine-engaging member reachesengine-engaging position, and also including a planet carrier whichcontinues to rotate with said motor, and means for stopping the rotationof said planet carrier and thereby causing the rotation of said motor tobe communicated to said engine-engaging` member, by way of said orbitalelement.

GILBERT.

